Method and apparatus for stacking articles



Aug. 29, 1967 J. H. THf-DICK 3,338,43

METHOD AND PPAHATUS FOR STACKING ARTICLES Filed Deo. 9, 1965 2 Sheets-Sheet l INVENTGR JOHN H. THED/C'K ug 29, 1967 J. H. THEDICK 3,338,431

METHOD AND APPARATUS FOR STACKING ARTICLES Filed Deo. 9, 1965 2 Sheets-Sheet 2 I NVENTOR.

United States Patent 3,338,431 METHOD AND APPARATUS FOR STACKING ARTICLES John H. Thedick, Klamath Falls, Oreg., assignor to Weyerhaeuser Company, Tacoma, Wash., a corporation of Washington Filed Dec. 9, 1965, Ser. No. 512,673 8 Claims. (Cl. 214-6) This invention relates to a method and apparatus for stacking articles and more particularly to a method and apparatus for stacking articles of random width with a uniform distribution of space between each article in any one layer.

In the handling of several articles having random widths, there is a need for an automatic means for stacking such random width articles in neat stacks and distribu'ting the articles in any one layer of the stack in a manner so that the edges of the stack are uniform and the spacing between each article in each layer is uniform. If the side edges of the stack are uniform but the spacing between the articlesis not uniform, it is possible that as subsequent layer's of articles are stacked, they will become lodged in the too large gaps between the articles in the next lower layer.

In the handling of articles having uniform width, there is a need for an automatic means for stacking such articles in a stack with uniform spacing between each article in each layer so that air may be circulated through the stack and reach all the side edges of the articles. There is also a need for means to automatically stack articles having uniform width or random wid-th with the side edges of the stacks indented and projected alternately from the subsequent layers of the materials in the stack, so that the stack will have a brick-like laid joint from top to bottom and be more physically secure and less likely t fall apart during handling.

It is therefore the object of this invention to provide an improved method and means for stacking articles in layers having uniform spacing between each article in any one layer.

It is a further object of this invention to provide a method and means for stacking articles of random widths and distributing the variations in width from the stack width over the course of the articles, leaving uniform spaces between each article in each layer.

It is still a further object of this invention to provide a method and means for stacking arti-cles to provide a stack having alternately indented and projected side edges of adjacent layers. Other related features and objects of the invention will become more fully apparent as the following description is read in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a partial side elevation view of the stacking apparatus illustrating the general arrangement of the components needed to form one sta-ck in accordance with the present invention;

FIGURE 2 is a partial side elevation view of the stacking apparatus of FIGURE 1 illustrating the initial position of the apparatus as the transfer mechanism moves from the feeding station to an article laying position;

FIGURE 3 is a partial side elevation view of the stacking apparatus shown in FIGURE 1 illustrating a second position where the articles of a new layer are being positioned .on a` previously laid layer; and

FIGURE 4 is a partial side elevation view of the stacking apparatus of FIGURE l showing it near the end of the operating cycle.

Referring to the drawings with more detail, there is seen in FIGURE l the general arrangement of the stacking apparatus 1. The basic components of the stacking apparatus 1 are the article feed conveyer 5, the article stack support assembly 20, and the transfer assembly 30. A full description of a suitable assembly having these components is provided in my copending application Ser. No. 512,642, filed Dec. 9, 1965. It is sufficient to relate here that articles are conveyed to the in-feed station 4 by means of feed conveyer 5, which consists of a conveyer support 6 which includes rollers 7 for supporting the articles being conveyed. The transfer assembly 30 is movable from the in-feed station 4 to a stacking position over the stack support assembly 20, which includes stack support members 21 whichare guided for vertical movement on elevation guide frame members 22.

The article transfer assembly 30 includes suitable drive means, not shown, which act through the shaft 37 to move drive arms 38, which are connected by means of shaft 40 to support fingers 41. Abutments 39 on one end of the drive arms 38 are engageable with abutments 42 on support fingers 41 when the ngers 41 are approximately 90 from the drive arms 38, such as is shown in FIGURE l. At the other end of support lingers 41 is laying end 46.

As shown in FIGURE 1, the upper end of the frame member 22 may include stripping members 58 which may have a flared-out section 59. The right-hand edge of the stack is coincident with plane a. The left-hand edge of the stack is coincident with the plane c. The maximum article layer width is the distance between plane a and c. To measure the distance between the maximum layer Width and the actual width of the articles being transferred from the in-feed station 4 to the first stack laying point, which lies in plane c, there is provided at the in-feed station 4 a course width measuring assembly 90, which includes limit switches 91 which are further identified as switches w, x, y, and z. As shown in FIG- URE l, the distance between the maximum layer width and the width of articles on the support fingers 41 is between w and x, and this is represented as the distance x between plane a and the plane b.

To provide a means for stripping the articles, denoted as 85, 86, 87 and 88, from lingers 41 onto the previously laid articles 81, 82, 83 and 84, which are supported on the stack support member 21, there is provided an adjustable stripping assembly 65.V This assembly includes at least one plunger 66, which has at one end a stripping surface 67 and at its bottom side a rack 68. The plunger 66 is mounted telescopi-cally in a plunger housing 69 and is driven by a plunger drive assembly 70, which includes pinions 71 keyed to and mounted upon drive shaft 72. The pinions 71 are engageable with the rack portion of the plungers 66 and are also engageable at one end of shaft 72 with the drive rack 73, which is in turn connected through link 74, through a nut 75 and screw assembly 76 to a drive motor 77. The drive motor 77, through suitable controls, is electrically connected to course width measuring assembly 90 to initially position the plunger 66 and its surface 67 the appropriate distance away from the plane a, as indicated by the last to actuate of the limit switches 91. A plunger retract lobe 95 may be mounted on shaft 37 to contact plunger retract limit switch 96 at the proper time to actuate the motor 77 to retract the plunger 66 from the plane b to the plane a.

In operation the transfer assembly is positioned through appropriate drive means and drive arms 38 so that fingers 41 are at the in-feed station 4 to receive articles 85, 86, 87 and 88. The distance, in this case x, between the maximum article layer width and the width of the articles from one edge of article 85 to the extreme edge of article 88 is measured by means of course width measuring assembly 90 through the action of limit switches 91. The motor 77 is actuated to extend the plunger 66 until the stripping surface 67 is in plane b which is displaced from the plane a a distance equal to the distance measured by the limit switches 91.

Referring now to FIGURE 2 there is seen that the article transfer assembly 30 has moved the fingers 41 from the in-feed station 4 to the position where the stripping surface 67 engages one edge of the article 85 to strip it and the other articles 86, 87 and 88 off the fingers 41.

Referring now to FIGURE 3 there is seen that the drive arms 38 have continued their movement so that the action of the stripping surface 67 and the continued withdrawal of the fingers 41 have caused the first article 88 to fall from the laying end 46. When the laying end 46 was positioned at the point designated plane d, the article 88 was mainly supported by the article 84 below with its lefthand edge coincident with the plane c, and at this point the plunger retract lobe 95 engaged the plunger retract limit switch 96 to actuate the motor 77 to retract the plunger 66. As the fingers 41 continue their withdrawal, the speed of the withdrawal of the laying end 46 from the plane d is proportional to the travel of the plunger 66 so that during the same time that the laying end 46 moves from the plane d to the plane a, the stripping surface 67 moves from the plane b to the plane a.

Referring now to FIGURE 4 it is seen that the result of this and the proportional movement between the laying end 46 land the stripping surface 67 is to divide the space x equally between the adjacent articles 85, 86, 87 and 88. This result is achieved Vwhether or not the articles are of equal or random widths.

When the articles are of equal width and the total width of each course is less than the distance between planes a and c, the result is a very unstable stack.l To provide a stable stack, it is possible to alternate the left and right edges of the stack so that they are indented and projected one above the other, and in this way the gaps between the articles in one layer do not line up with the gap between the articles in the adjacent layer. This can be provided in the present equipment by introducing a false signal from the measuring assembly 90 or the retract limit switch 96, or both every other cycle of the transfer mechanism 30. With the course evening adjustable stripping assembly 65, it is possible to place the articles in each course with a uniform gap spacing between each individual article. This eliminates any large gap in the center of the stack into which articles of succeeding courses might lodge. v

It is therefore seen that I have disclosed an improved method and apparatus for stacking articles.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. An apparatus for stacking articles which comprises in combination:

article feed conveying means,

article stack support means,

article transfer means for receiving articles at said feed ymeans and transferring them to said stack support means, stripping means positioned near said stack support means for presenting surface means in the path of said articles on said transfer means causing said articles to form a layer on said stack support as said transfer means moves relative to said stripping means,

measuring means for measuring the difference between the width of the article load on said transfer means and the desired stack Width,

drive means for extending and retracting said stripping surface means a distance from one edge of a desired stack,

transfer means limit switch means for indicating that said transfer means is in a first position to form a layer of articles on said stack support means and in a position in its passage from said first position to the last position for forming a layer,

said drive means responsive to said measuring means to extend said stripping surface the 'measured distance away from one edge of a desired stack to a first surface position and responsive to said transfer means limit switch means to retract said stripping surface from said first surface position to a second surface position in a plane coincident with the desired stack edge at the same time that said limit switch indicates that said transfer means has moved from said first layer forming position to said last position for forming a layer.

2. The apparatus of claim 1 wherein said transfer means includes retract lobe means for actuating said transfer means limit switch means.

3. The apparatus of claim 1 wherein said measuring means is positioned adjacent said feed conveying means and includes at least two limit switch means for measuring increments of distance between the edge of said articles on said transfer means and the maximum width of a desired stack.

4. The apparatus of claim 1 wherein said stripping means includes surface means and plunger means,

said plunger means being telescopically mounted in a housing and actuated by drive means.

5. The apparatus of claim 4 wherein said plunge-r means includes plunger rack means,

said drive means includes drive rack means for rotating drive pinion means, and

said plunger rack means being engaged by said drive pinion means.

6. The apparatus of claim 4 wherein said measuring mea-ns is positioned adjacent said feed conveying means and includes at least two limit switch means measuring increments of distance between the edge of said articles on said transfer means and the maximum width of a desired stack,

said transfer means includes retract lobe means for actuating said transfer means limit switch means.

7. A method for stacking articles comprising the following steps:

(a) feeding articles to an article transfer means at an in-feed station,

(Ib) measuring the distance x between the maximum article layer width and the width of the articles on said transfer means,

(c) positioning stripping means to present at least one surface in the path of said articles on said transfer means at a first surface position a distance x away from a plane coincident with one side edge of a desired article stack,

(d) moving the laying end of said article transfer means from said in-feed station to a first stack laying point lying in a planecoincident with the other side edge of said desiredv article stack,

(e) contacting one side edge of said articles on said transfer means with said stripping surface means causing the other side edge of said articles to fall 5 from said laying end of said transfer means at said iirst stack laying point,

(f) moving said laying end of said transfer means from said rst stack laying point to a second point lying in said plane coincident with said one side of said desired article stack,

(g) sliding the first article from laying end to fall with one edge lying in a plane coincident with said other side edge of said desired article stack, and then (h) moving said stripping surface means from said first surface position to reach said second point at the same time that it is reached by said laying end.

8. The method of claim 7 wherein on alternate cycles the steps of (b) and (c) include the layers of the stack to be alternately indented and recessed an amount equal to said increment distance.

References Cited 5 UNITED STATES PATENTS 1,188,137 6/1916 Baker et al 214-6 3,122,241 2/ 1964 Lawson 214-6 FOREIGN PATENTS 10 433,561 10/1929 Germany.

GERALD M. FORLENZA, Primary Examiner. I. E. OLDS, Assistant Examiner.

addition of an increment distance to cause the article 15 

1. AN APPARATUS FOR STACKING ARTICLES WHICH COMPRISES IN COMBINATION: ARTICLE FEED CONVEYING MEANS, ARTICLE STACK SUPPORT MEANS, ARTICLE TRANSFER MEANS FOR RECEIVING ARTICLES AT SAID FEED MEANS AND TRANSFERRING THEM TO SAID STACK SUPPORT MEANS, STRIPPING MEANS POSITIONED NEAR SAID STACK SUPPORT MEANS FOR PRESENTING SURFACE MEANS IN THE PATH OF SAID ARTICLES ON SAID TRANSFER MEANS CAUSING SAID ARTICLES TO FORM A LAYER ON SAID STACK SUPPORT AS SAID TRANSFER MEANS MOVES RELATIVE TO SAID STRIPPING MEANS, MEASURING MEANS FOR MEASURING THE DIFFERENCE BETWEEN THE WIDTH OF THE ARTICLE LOAD ON THE SAID TRANSFER MEANS AND THE DESIRED STACK WIDTH, DRIVE MEANS FOR EXTENDING SAID RETRACTING SAID STRIPPING SURFACE MEANS A DISTANCE FROM ONE EDGE OF A DESIRED STACK, 